Patients with diffuse idiopathic skeletal hyperostosis do not have increased peripheral bone mineral density and geometry.

Abstract

Recent studies have suggested that areal BMD (aBMD) measured by DXA is elevated in patients with DISH. We used peripheral QCT (pQCT) to assess volumetric BMD (vBMD) and bone geometry of the radius, tibia and the third metacarpal bone. Patients with established DISH and a control group of healthy individuals were recruited. pQCT measurements were performed at the distal epiphyses and mid-shafts of the radius, the tibia and the third metacarpal bone. At the epiphyses cross-sectional area (CSA), total BMD and trabecular BMD were measured. At the shafts, total bone CSA, cortical CSA, cortical wall thickness and cortical BMD were determined. In addition, muscle and fat CSA of the forearm and lower leg were assessed. Bone parameters were compared between the two groups using independent t-tests. Thirty DISH patients and 30 controls comparable with regard to age and height were included in this study. None of the measured bone parameters differed between groups. In contrast to suggestions based on DXA, pQCT revealed that DISH patients do not have increased vBMD and bone geometry in the appendicular skeleton. Ossification at tendon or ligament insertion sites may lead to overestimation of aBMD if assessed by DXA.